| 摘要 |
PROBLEM TO BE SOLVED: To prevent resistance from scattering in advance by using a resistor with fixed resistance. SOLUTION: A device is provided with a piezoelectric pick-up 1 for generating an electric charge according to the acceleration of vibration and a charge amplifier 2 for generating a voltage signal corresponding to the above acceleration based on an electric charge being generated by the piezoelectric pick-up 1. In this case, the charge amplifier 2 is provided with an electric charge-voltage conversion circuit 3 for converting the level of the electric charge corresponding to the above acceleration based on the electric charge being generated by the piezoelectric pick-up 1 to a voltage and for generating a voltage signal corresponding to the voltage and a gain regulator 4 where a constant resistance value is weighted to each bit, a digital control input signal for controlling sensitivity is converted to an analog signal, and sensitivity corresponding to a voltage signal being sent from the electric charge-voltage conversion circuit 3 is set and then a voltage signal is generated as an output signal.
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